Gzip Compress / Decompress

Gzip, zlib and raw deflate for text and files, with sizes and compression ratio.

Runs locally · nothing uploaded
Text
Compressed (Base64)

What it does

Gzip shows up everywhere: HTTP responses, log archives, message queues and Base64 blobs inside JSON or databases. This tool compresses and decompresses with the browser’s built-in CompressionStream and DecompressionStream.

  • Three formats: gzip (RFC 1952, .gz), deflate with a zlib header (RFC 1950, what most libraries call “deflate”), and deflate-raw (RFC 1951, used inside ZIP files and some APIs).
  • Text mode compresses as you type and shows the result as Base64. To decompress, paste Base64 (H4sI...) or hex (1f8b...); Auto-detect recognizes the format from the header bytes.
  • File mode compresses any file to .gz and stores the original file name and date in the gzip header, exactly like the gzip command, so gunzip -N restores the name. Dropping a .gz file decompresses it and reuses the stored name.
  • Stats: original and compressed size, ratio and space saved.
  • Clear errors: wrong format, truncated data and trailing garbage are reported as such.

How to use it

Choose Text or File, pick a format (gzip is the usual choice) and type, paste or drop. Copy the Base64 with Ctrl+Enter, or download the raw bytes.

Limitations

The browser API does not expose compression levels, so results are close to, but not always byte-identical with, gzip -9. Very old browsers without CompressionStream are not supported; the page tells you if yours is one of them.

Privacy

Compression runs locally; files never leave your computer. Only the text input is kept in local storage.